1. Field of the Invention
The present invention relates to a charge wire, a method of manufacturing the charge wire, a charge device including the charge wire, and an image forming device including the charge device. The charge wire is for charging an object to be charged such as a photosensitive drum and is used in image forming devices for forming images such as by electrophotographic techniques.
2. Description of the Related Art
There have been known electrophotographic image forming devices, such as laser printers, including a charge unit, a photosensitive drum on which a desired image is to be supported, a laser beam scanner, a developing unit, a transfer unit, and a fixing unit. First, the charge unit charges the surface of the photosensitive drum to a uniform charge. Then, the laser beam scanner irradiates the surface of the photosensitive drum with light corresponding to a desired image. This forms an electrostatic latent image on the surface of the photosensitive drum corresponding to the desired image. Next, the developing unit develops the electrostatic latent image with toner to form a visible image. The transfer unit then transfers the visible toner image onto a transfer member such as a paper sheet. Finally, the fixing unit fixes the toner image onto the sheet.
Various types of charge units are available for charging the surface of the photosensitive drum. For example, corotoron charge units and scorotoron charge units are known. Both corotoron and scorotoron charge units include a C-shape shield and a wire stretched taut within the shield. The charge wire is made from tungsten steel from 60 .mu.m to 100 .mu.m. In scorotoron charge units, a grid having control electrodes is disposed at the open side of the shield. A high voltage is developed between the wire and the shield so that a corona discharge occurs.
However, a problem exists in corotoron and scorotoron charge units. As image forming processes are repeatedly performed, products resulting from the discharge process cling to the surface of the charge wire. Substances clinging to the charge wire include mainly silicon. A portion of the silicon component clinging to the charge wire is presumed to be from toner from the developing unit and rubber from developing rollers in the developing unit. Another portion of the silicon component is presumed to be from silicon used in the structure of the printer that has oxidized on the charge wire by energy produced during discharge.